Velocity sensitive check valve



Feb. l5, 1966 L. l.. ARNEs 3,234,961

VELOCITY SENSITIVE CHECK VALVE Filed Aug. a, 196s INVENTOR y/f /Wes.

United States Patent Gflice 3,234,961 Patented Feb. 15, 1966 3,234 961 VELOCITY SENSITFVE CHECK VALVE Lyle L. Ames, Racine, Wis., assignor to Walker Manufacturing Company, Racine, Wis., a corporation of Dela- Ware Filed Aug. s, 196s, ser. No. 300,861 1 claim. (el. 137-517) This invention relates to hydraulic jack apparatus and valve means associated therewith.

The invention is particularly directed to a velocity sensitive check valve for use with a hydraulic automobile jack or the like having a self contained hydraulic liuid reservoir and manually operable pump, and which is adapted to be additionally operable by a remote hydraulic fluid reservoir and a remote power operable pump and a remote release control. When a jack is being lowered under load by return flow of hydraulic fluid to reservoir, the rate of return iiow of hydraulic fluid should be closely controlled. A rupture in the return passage for the hydraulic liuid may result in a sudden surge of hydraulic fluid causing the jack to be lowered at a dangerously fast rate.

The primary object of the present invention is to provide valve means sensitive to the rate of flow of a fluid in a passage and actuable in response to a predetermined high rate of liow to close the flow passage. More speciically, the object of the invention is to provide a velocity sensitive valve means in a hydraulic passage connecting a jack unit to a remotely located pump and fluid reservoir to prevent dangerously fast return of hydraulic fluid during lowering movement of the jack when using the remote release, or in the event of a ruptured hydraulic conduit.

The inventive principles are hereinafter disclosed in detail by reference to an illustrative embodiment of the invention wherein:

FIGURE 1 is a diagrammatic View of a jack unit incorporating t-he inventive principle;

FIGURE 2 is a partial side elevational View, in section, of a portion of the jack unit;

FIGURE 3 is an enlarged sectional view of valve means associated with the jack unit shown in FIG. 2; and

FIGURE 4 is an enlarged sectional view of the valve means in another operational position.

Referring now to FIG. 1, a hydraulic jack system is schematically shown and comprises a generally conventional self-contained jack unit 10, a special fitting and valve connection 11, and a remote source of high pressure hydraulic fluid. The special tting and valve connection is adapted to connect the self-contained jack unit to a remote liuid reservoir and pump 12 via suitable hydraulic conduits 13, 14. The self-contained jack unit includes a manually operable pump 15 for withdrawing hydraulic liuid from a reservoir 16 through suitable valve and passage means 17, and for forcing hydraulic fluid to a jack cylinder 18 through suitable valve and passage means 19 to raise the jack. Suitable release valve and return passage means 20 are provided to return hydraulic fluid to the reservoir 16 under pressure of a load during lowering of the jack.

Referring now to FIGURE 2, the jack unit 10 is shown to comprise a base portion 26 in which the pump 15, the hydraulic reservoir 16, and the various valves and passages 17, 19, 20 are mounted. The return passage means may be controlled by a conventional release mechanism. The details of construction of these portions of the pump are well known in the pumping art and therefore not described in greater detail.

The present invention relates to the passage and valve means 11 connecting the jack unit 10 to the remote pump 12 which may be, for example, of an air operated type such as found in automobile service stations, or the like. In the illustrative embodiment, the valve means 11 is integrally mounted on the base 26 which is provided with a boss 38 having a tapered opening 40 provided` with internal pipe threads 42 and adapted to receive a connecting fitting 44 having corresponding external pipe threads to form a sealed connection in the opening 40. Suitable passage means 13 connect the opening 40 to the conventional jack passage means to deliver hydraulic fluid from the remote pump to the cylinder and to return hydraulic liuid from the cylinder to the remote reservoir. The conventional release mechanism may be utilized to control return iiow.

Velocity sensitive check valve means are mounted in a fitting 4S which is connected to the fitting 44 by suitable pipe threads 50. Referring now to FIGURE 3, one end 52 of the fitting 4S is enlarged and is provided with suitable internal coupling threads 56. The litting is further provided with a central portion 58 of reduced diameter on which the pipe threads 50 are formed. The other end 60 of the fitting is reduced in diameter and has a chamfered edge 62 adapted to be matingly engaged with a corresponding conical surface provided in the litting 44 as shown at 63 in FIG. 2.

A central bore extends through the fitting and comprises axially spaced portions 63, 64, 65, 66 of varying diameter. The bore portions 63, 65 are of substantially constant diameter and the separating bore portion 64 is of reduced diameter and provides an orifice therebetween. The reduced diameter central portion 64 is connected to the spaced portions 63, 65 by conical surfaces 70, 72. Conical surface 70 is adapted to provide a valve seat for a check valve 73. The end of the passage portion 65 is threaded as indicated at 74 and is adapted to receive a threaded plug 76 having a centrally located bore 78 providing a fluid passage of `reduced diameter therethrough. The plug is threadably adjustable and a suitable tool slot 79 may be provided for adjustment.

The check valve is in the form of a ball which is smaller in diameter and confined in the bore 63 by a transverse pin 82 mounted in the end portion 60 of the valve fitting 43. A valve stem 84 is mounted in the central bore and comprises a central flange portion 86 on which a compression spring 88 is seated. A support portion 90 of the stem extends from the flange 86 toward the plug 76 and supports the stem within the coils of the spring S8, which is seated at the other end against plug 76. Control pressure is exerted by the spring on the stem through the ange 86 and the amount of pressure exerted by the spring may be controlled by threadably adjusting the position of the plug 76. A valve controlling portion 92 of the stem extends from the flan-ge 86 toward the ball valve through the reduced bore portion 64 and is adapted to abuttingly engage the side surface of the ball valve. The diameter of the stem portion 92 is substantially less than the diameter of the central orifice 64. The length of the stem portion 92 and the bias of the spring 88y is such as to normally maintain the ball valve 73 in an open position seated on the pin 82. Under certain predetermined high pressure conditions in the bore 63 during return liow of liuid from the ram cylinder to the remote pump, the bias of the spring 818 is adapted to be overcome to allow the ball valve to seat on the valve seat and close the central bore to prevent further flow of uid until pressure conditions in the bore are reduced.

In normal operation, the ball valve is in the position shown in FIGURE 3 spaced a substantial distance from the valve seat 70 and p'remitting flow of uid in both directions through the orilice 64. During delivery of hydraulic fluid to raise the jack the valve is always maintained in the open position. When the hydraulic iluid under pressure in the jack is returned through the valve by actuation of the release mechanism, the check valve 73 is eifective to prevent dangerously fast return ow of hydraulic uid by closing the uid passage in response to extraordinary high pressure conditions in the uid passage which might be caused, for example, by sudden surges of uid ow if the release mechanism is opened too fast or if the conduit connecting the jack to the remote reservoir might rupture. Accordingly, whenever sudden surges of the fluid enter the bore 63 and create a predetermined high pressure, the ball valve 73 is closed against the bias of compression spring 88 and seats on the seat 70. Thus, further ow through the orice 68 is prevented until the pressure in the passage 63 is reduced and the compression spring 88 is again able to move the ball valve off of the valve seat. As the ball valve closes, the bias of the compression spring increases and the size of the ow passage between the ball valve and the valve seat gradually diminishes. In this manner, the rate of ow of hydraulic fluid is gradually reduced until the ball valve is fully seated. Since the reservoir pressure is substantially atmospheric, the ball check valve 73 will be responsive to pressure in the conduit 63 during the reverse flow operation previously described. It is to be understood, however, that the ball valve 73 is responsive to the pressure differential across it and will thus close in response to high pressure differentials.

The inventive principles have hereinbefore been described in detail by reference to an illustrative embodiment of the invention. Since the illustrative embodiment is susceptible to various changes and modifications without deviating from the inventive principles, it is intended that the scope of the appended claims be construed to include various alternative embodiments of the invention.

The invention claimed is:

In a hydraulic jack system, a hydraulic iluid line, a fitting in said line, a central bore extending through said tting, a rst portion of said bore being enlarged, the next adjacent portion of said bore being provided with internal threads, a plug threadedly mounted in said threaded portion of said bore and having an enlarged head portion mounted in said enlarged portion of said bore, said plug having a central bore connecting said enlarged portion of said bore to the threaded portion of said bore, a reduced central portion in said next adjacent portion of said bore forming an orioe, a valve chamber formed-in said bore beyond said orice, a ball valve mounted in said valve chamber, means confining said ball valve in said valve chamber for movement between an open position and a closed position relative to said orice, and bias means mounted in said next adjacent portion of said bore, a portion of said bias means extending through said orifice and controllably engaging said ball valve.

References Cited by the Examiner UNITED STATES PATENTS 577,489 2/1897 Mills. 1,069,863 8/1913 Despins 60-52 2,092,738 9/1937 Rodgers. 2,098,119 11/1937 White 137-517 X 2,245,271 6/1941 Guill 137--517 2,676,573 4/1954 Abbe 137-517 X 3,106,226 10/1963 Machen 138-45 JULIUS E. WEST, Primary Examiner. 

